Nucleic acid sequences encoding Bau, a Bin1 interacting protein, and vectors and host cells containing same

ABSTRACT

A murine cDNA clone encoding a BIN1-Associated U1-specific protein (Bau) are provided. Also provided are methods of using the nucleic acid sequences, polypeptides, and antibodies directed against same in the diagnosis and treatment of cancers, hyperplastic disease states, or degenerative diseases.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application No. 60/025,482, filed Aug. 29, 1997.

FIELD OF THE INVENTION

This invention relates generally to cancer diagnosis and therapy, and more specifically, to cancers associated with activation of the Myc oncoprotein and/or loss of Bin1 tumor suppression.

BACKGROUND OF THE INVENTION

There is a significant need for effective therapies against many types of cancers, especially carcinoma, which is often untreatable in its advanced states. Cell regulation by the Myc oncoprotein offers an attractive focus for therapeutic development. Myc is deregulated in a wide variety of cancers, including most carcinomas, through genetic and epigenetic mechanisms M.D. Cole, Ann. Rev. Genet., 20:361-384 (1986)!. Thus, Myc-regulated mechanisms are logical targets for developing novel and broadly applicable therapeutic strategies.

Myc acts at the intersection of pathways that control cell division, differentiation, and apoptosis. in normal cells, Myc is rapidly induced following mitogenic stimulation and remains elevated throughout the cell cycle Evan and Littlewood, Curr Opin Genet Dev, 3: 44-49 (1993)!. Induction of Myc is sufficient to drive cell proliferation M. Eilers, et al., Nature, 340: 66-8 (1989)!, while inhibition of Myc can block mitogenic signals and facilitate cell differentiation R. Heikkila, et al., Nature, 328: 445-448 (1987); J. T. Holt, et al., Mol Cell Biol, 8: 963-973 (1988); K. D. Hanson, et al., Mol Cell Biol, 14: 5748-5755 (1994)!. Significantly, Myc can induce apoptosis D. S. Askew, et al., Oncogene, 6: 1915-1922 (1991); G. I. Evan, et al., Cell, 69: 119-128 (1992)!, if its expression is uncoupled from the orchestration of other cell cycle regulatory events G. I. Evan, et al., cited above!. Clinical evidence indicates that loss of the apoptotic response is associated with malignant conversion. Therefore, reactivation or derepression of this response would be desirable. Myc-activated death in epithelial cells (the precursor cell type to carcinoma) is p53-independent D. Sakamuro, et al., Oncogene, 11: 2411-2418 (1995)!, a useful feature because p53 function is often lost in carcinoma Levine, Ann Rev Biochem, 62: 623-651 (1993)!. Thus, using Myc-activated death mechanisms is attractive, since the tumor cell could be attacked without regard to its p53 status.

Bin1 is a 451 amino acid Myc-interacting nuclear phosphoprotein D. Sakamuro, et al., Nature Genet, 14: 69-77 (1996)!, which has been implicated in the mechanism by which Myc induces apoptosis. Bin1 has several features of a tumor suppressor that is lost in breast and prostate carcinoma, where loss of apoptotic potential is tantamount to malignant conversion. First, Bin1 suppresses malignant cell transformation by Myc, but also by adenovirus E1A and by mutant p53, which act by Myc-independent mechanisms. Second, while normally ubiquitously expressed, Bin1 is frequently missing in breast and prostate carcinoma cell lines and primary tumors. Third, these deficits in expression appear to be functionally significant, because ectopic expression of Bin1 inhibits the growth of tumor cells which lack endogenous Bin1. Fourth, the N-terminal region of Bin1, termed the BAR domain, is closely related to a breast cancer-associated autoimmune antigen (amphiphysin) and a negative regulator of the yeast cell cycle (RVS167) D. Sakamuro, et al., cited above.!. Finally, the human Bin1 gene maps to chromosome 2q14 D. Negorev, et al., Genomics, 33: 329-331 (1996)!, within a mid-2q region that is among the more frequently deleted loci in metastatic prostate cancers M. L. Cher, et al., Canc Res, 56: 3091-3102 (1996)!.

The murine and human BIN1 sequences, provided herein as FIGS. 2 and 3, are described in more detail in WO 96/34627. Of particular interest is the unique-1 (U1) region (located between aa 225-250) D. Sakamuro et al, cited above; R. Wechsler-Reya, et al., Cancer Res, 57:3258-3263 (1997)!, which mediates efficient cell growth inhibition through both Myc-dependent and Myc-independent mechanisms. U1 is encoded by exon 9 in the human Bin1 gene, located adjacent to the alternatively spliced exon 10.

There remains a need in the art for compositions and methods of regulating a deregulated Myc protein and of treating and diagnosing cancers associated with the Myc oncoprotein and/or undesirably low Bin1 levels.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a murine cDNA clone of a BIN1-Associated U1-specific protein (Bau) SEQ ID NO:1 and the polypeptide encoded thereby, SEQ ID NO:2.

In yet another aspect, the present invention provides a vector comprising a mammalian nucleic acid sequence encoding a BIN1 protein and a host cell transformed by such a vector. Alternatively, this vector may be used in gene therapy applications.

In still another aspect, the invention provides an oligonucleotide probe comprising a nucleic acid sequence as defined herein. Also provided is an antibody raised against a Bau protein or peptide thereof.

In yet a further aspect, the present invention provides a diagnostic reagent for cancers, involving Myc, inappropriately high Bau levels, or inappropriately low Bin levels, comprising an oligonucleotide probe or an antibody of the invention.

Further provided is a therapeutic reagent comprising a polypeptide, anti-idiotype antibody, or gene therapy vector of the invention.

Still another aspect of the invention provides a method of treating cancers involving Myc by administering a therapeutic reagent of the invention.

Other aspects and advantages of the present invention are described further in the following detailed description of the preferred embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B is a murine Bau cDNA sequence SEQ ID NO:1! and the murine Bau polypeptide encoded thereby SEQ ID NO:2!.

FIG. 2 is a murine cDNA sequence SEQ ID NO:3! encoding a BIN1 polypeptide SEQ ID NO:4!.

FIGS. 3A-3C is a human cDNA sequence SEQ ID NO:5! encoding a BIN1 polypeptide SEQ ID NO:6!.

FIG. 4 is a bar chart illustrating Bau suppression of malignant transformation of rat embryo fibroblasts by the adenovirus E1a oncoprotein.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides novel, isolated, nucleic acid Bau sequences which encode novel proteins which interact with BIN1 and bind thereto, fragments of these sequences and antibodies developed thereto. As described above briefly, BIN1 is a protein that interacts with the functionally critical Myc box regions at the N-terminus of the Myc oncoprotein and which is associated with tumor suppression and apoptosis. BIN1 is described in more detail in the International Patent Application which published as WO 96/34627 on Nov. 7, 1996 and U.S. Pat. No. 5,605,830, as well as in co-owned, co-pending U.S. patent application Ser. No. 08/652,972, now U.S. Pat. No. 5,723,581 which are incorporated herein by reference.

The Bau nucleic acid sequences, amino acid sequences and antibodies of the invention are useful in the detection, diagnosis and treatment of cancers or other disorders associated with inappropriate BIN1 levels and/or deregulation, deficiency or amplification of the c-Myc oncogenes. These aspects of the invention are discussed in more detail below.

I. Nucleic Acid Sequences

The present invention provides mammalian nucleic acid sequences encoding a 293 amino acid polypeptide, termed herein Bau. The nucleic acid sequences of this invention are isolated from cellular materials with which they are naturally associated.

The Bau cDNA was isolated in a yeast two hybrid screen for polypeptides that could specifically associate with the U1 domain (aa 225-250) of the human BIN1 protein SEQ ID NO:6!. The U1 region is a functionally important region of BIN1 and has a role in protein-protein interaction. U1 contains several amino acid sequence motifs which are found in regulators of the cell cycle and chromosome function. Two .sup.˜ 10 residue motifs show relatedness to the yeast proteins p93dis1 Nabeshima et al, Genes Dev., 9:1572-1585 (1995)! and RED1 Thompson and Roeder, Mol. Gen. Genet., 218:293-301 (1989)!, which are involved in chromosome segregation. An additional sequence motif is shared with a region of the SV40 virus T antigen protein (aa 5-35) which is implicated in its cellular immortalization activity Conzen and Cole, Oncogene, 11:2295-2302 (1995)!. Notably, the BIN-T antigen similarity is of the form DψLXGXE SEQ ID NO:7! (the greek psi represents a hydrophobic amino acid), which is reminiscent of the (D)LXCXE SEQ ID NO:8! motif which mediates protein-protein interactions with the retinoblastoma (Rb) protein, an important regulator of the G1 phase of the cell cycle. A connection to Rb is intriguing, because an Rb-sized .sup.˜ 110 kD protein(s) is specifically coimmunoprecipitated with BIN1 from cell lysates by anti-BIN1 monoclonal antibodies. Further, in cell transformation experiments, U1 deletion reduced the activity of BIN1 to inhibit the oncogenic activity of MYC, and abolished the ability of BIN1 to inhibit the oncogenic activity of the adenovirus E1A oncoprotein, which is functionally related to MYC and which must inactivate Rb to transform cells. The ability of the 293 aa Bau polypeptide to inhibit E1A-mediated cell transformation, similar to BIN1, indicates its direct role in regulating U1. Taken together, the data indicates that Bau possesses anti-oncogenic activity, possibly related to apoptosis. Furthermore, the data suggests that Bau influences or mediates Bin1 activity through interactions with U1.

Thus, in one embodiment, the invention provides a Bau nucleic acid sequence which is selected from all or part of the murine cDNA clone, SEQ ID NO: 1. However, the present invention is not limited to these nucleic acid sequences.

Given the sequences of SEQ ID NO: 1, one of skill in the art can readily obtain the corresponding anti-sense strands of these cDNA and genomic sequences. Further, using known techniques, one of skill in the art can readily obtain the human sequences corresponding to these cDNA sequences or the corresponding RNA sequences, as desired.

Similarly, the availability of SEQ ID NO: 1 of this invention permits one of skill in the art to obtain other species Bau homologs, by use of the nucleic acid sequences of this invention as probes in a conventional technique, e.g., polymerase chain reaction. Allelic variants of these sequences within a species (i.e., nucleotide sequences containing some individual nucleotide differences from a more commonly occurring sequence within a species, but which nevertheless encode the same protein), may also be readily obtained given the knowledge of this sequence provided by this invention.

The present invention further encompasses nucleic acid sequences capable of hybridizing under stringent conditions see, J. Sambrook et al, Molecular Cloning: A Laboratory Manual, 2d ed., Cold Spring Harbor Laboratory (1989)! to the sequences of SEQ ID NO: 1, their anti-sense strands, or biologically active fragments thereof. An example of a highly stringent hybridization condition is hybridization at 2×SSC at 65° C., followed by a washing in 0.1×SSC at 65° C. for an hour. Alternatively, an exemplary highly stringent hybridization condition is in 50% formamide, 4×SSC at 42° C. Moderately high stringency conditions may also prove useful, e.g. hybridization in 4×SSC at 55° C., followed by washing in 0.1×SSC at 37° C. for an hour. An alternative exemplary moderately high stringency hybridization condition is in 50% formamide, 4×SSC at 30° C.

Also encompassed within this invention are fragments of the above-identified nucleic acid sequences. Preferably, such fragments are characterized by encoding a functional fragment of Bau, e.g., the Bin1-binding domain (nucleotides 231 to 674 of SEQ ID NO:1), an epitope, or another fragment characterized by having a desired biological activity. Generally, these oligonucleotide fragments are at least 15 nucleotides in length. However, oligonucleotide fragments of varying sizes may be selected as desired. Such fragments may be used for such purposes as performing the PCR, e.g., on a biopsied tissue sample. For example, one nucleotide fragment optimal for PCR is the fragment defined by nucleotides 231 to 674 within SEQ ID NO: 1. Other useful fragments may be readily identified by one of skill in the art by resort to conventional techniques, e.g., by computerized motif searching. Examples of such useful fragments include (with reference to SEQ ID NO:1) nt 48 to 527, which encode a coiled-coil domain; nt 312 to 362, which encode a signature motif; nt 294 to 356, which encode a cystatin motif; and nt 540 to 554, which encode a polyasparagine region.

The nucleotide sequences of the invention may be isolated by conventional uses of polymerase chain reaction or cloning techniques such as those described in obtaining the murine sequences, described below. Alternatively, these sequences may be constructed using conventional genetic engineering or chemical synthesis techniques.

According to the invention, the nucleic acid sequences SEQ ID NO: 1! may be modified. Utilizing the sequence data in these figures and in the sequence listing, it is within the skill of the art to obtain other polynucleotide sequences encoding the proteins of the invention. Such modifications at the nucleic acid level include, for example, modifications to the nucleotide sequences which are silent or which change the amino acids, e.g. to improve expression or secretion. Also included are allelic variations, caused by the natural degeneracy of the genetic code.

Also encompassed by the present invention are mutants of the Bau gene provided herein. Such mutants include amino terminal, carboxy terminal or internal deletions which are useful as dominant inhibitor genes. Such a truncated, or deletion, mutant may be expressed for the purpose of inhibiting the activity of the full-length or wild-type gene. These nucleic acid sequences are useful for a variety of diagnostic and therapeutic uses. Advantageously, the nucleic acid sequences are useful in the development of diagnostic probes and antisense probes for use in the detection and diagnosis of conditions characterized by inappropriate BIN1 levels, which may be associated with deregulation or amplification of c-MYC. The nucleic acid sequences of this invention are also useful in the production of mammalian, and particularly, murine and human BIN1 proteins.

II. Protein Sequences

The present invention also provides mammalian Bau polypeptides or proteins. These proteins are free from association with other contaminating proteins or materials with which they are found in nature. In one embodiment, the invention provides a murine Bau SEQ ID NO:2! polypeptide of 293 amino acids having a predicted molecular weight (MW) 34,137.

Further encompassed by this invention are fragments of the Bau polypeptides. Such fragments are desirably characterized by having Bau biological activity, including, e.g., the ability to interact with BIN1. An example of such a fragment is aa 62 to 209, which encompasses the Bin1-binding domain. Other useful fragments may be designed or obtained in any desired length, including as small as about 8 amino acids in length. Such a fragment may represent an epitope of the protein. Further, one of skill in the art can readily identify other functional fragments, e.g., by computer motif analysis. Examples of such useful fragments include (with reference to SEQ ID NO:2), aa 1 to 160 which is a coiled-coil domain; aa 89 to 105, which is a signature motif; aa 83 to 103, which is a cystatin motif; and aa 165 to 169, which is a polyasparagine region.

Also included in the invention are analogs, or modified versions, of the proteins provided herein. Typically, such analogs differ by only one to four codon changes. Examples include polypeptides with minor amino acid variations from the illustrated amino acid sequences of Bau (FIG. 1; SEQ ID NO:2); in particular, conservative amino acid replacements. Conservative replacements are those that take place within a family of amino acids that are related in their side chains and chemical properties. Also provided are homologs of Bau. Based on the sequence information provided herein, one of skill in the art can readily obtain Bau from other mammalian species. Such analogs and homologs are typically at least about 85% homologous with SEQ ID NO: 2, and more desirably, at least about 90% homologous, as determined by sequence comparison algorithms such as WU-BLAST2 (Washington University BLAST).

Additionally, the Bau proteins SEQ ID NO:2! of the invention may be modified, for example, by truncation at the amino or carboxy termini, by elimination or substitution of one or more amino acids, or by any number of now conventional techniques to improve production thereof, to enhance protein stability or other characteristics, e.g. binding activity or bioavailability, or to confer some other desired property upon the protein.

III. Expression

A. In Vitro

To produce recombinant Bau proteins of this invention, the DNA sequences of the invention are inserted into a suitable expression system. Desirably, a recombinant molecule or vector is constructed in which the polynucleotide sequence encoding Bau is operably linked to a heterologous expression control sequence permitting expression of the Bau protein. Numerous types of appropriate expression vectors are known in the art for mammalian (including human) protein expression, by standard molecular biology techniques. Such vectors may be selected from among conventional vector types including insects, e.g., baculovirus expression, or yeast, fungal, bacterial or viral expression systems. Other appropriate expression vectors, of which numerous types are known in the art, can also be used for this purpose.

Methods for obtaining such expression vectors are well-known. See, Sambrook et al, Molecular Cloning. A Laboratory Manual, 2d edition, Cold Spring Harbor Laboratory, New York (1989); Miller et al, Genetic Engineering, 8:277-298 (Plenum Press 1986) and references cited therein.

Suitable host cells or cell lines for transfection by this method include mammalian cells, such as Human 293 cells, Chinese hamster ovary cells (CHO), the monkey COS-1 cell line or murine 3T3 cells derived from Swiss, Balb-c or NIH mice may be used. Another suitable mammalian cell line is the CV-1 cell line. Still other suitable mammalian host cells, as well as methods for transfection, culture, amplification, screening, production, and purification are known in the art. See, e.g., Gething and Sambrook, Nature, 293:620-625 (1981), or alternatively, Kaufman et al, Mol. Cell. Biol., 5(7):1750-1759 (1985) or Howley et al, U.S. Pat. No. 4,419,446!.

Similarly bacterial cells are useful as host cells for the present invention. For example, the various strains of E. coli (e.g., HB101, MC1061, and strains used in the following examples) are well-known as host cells in the field of biotechnology. Various strains of B. subtilis, Pseudomonas, other bacilli and the like may also be employed in this method.

Many strains of yeast cells known to those skilled in the art are also available as host cells for expression of the polypeptides of the present invention. Other fungal cells may also be employed as expression systems. Alternatively, insect cells such as Spodoptera frugipedera (Sf9) cells may be used.

Thus, the present invention provides a method for producing a recombinant Bau protein which involves transfecting a host cell with at least one expression vector containing a recombinant polynucleotide encoding a Bau protein under the control of a transcriptional regulatory sequence, e.g., by conventional means such as electroporation. The transfected host cell is then cultured under conditions that allow expression of the Bau protein. The expressed protein is then recovered, isolated, and optionally purified from the culture medium (or from the cell, if expressed intracellularly) by appropriate means known to one of skill in the art.

For example, the proteins may be isolated in soluble form following cell lysis, or may be extracted using known techniques, e.g., in guanidine chloride. If desired, the Bau proteins of the invention may be produced as a fusion protein. For example, it may be desirable to produce Bau fusion proteins, to enhance expression of the protein in a selected host cell, to improve purification, or for use in monitoring the presence of Bau in tissues, cells or cell extracts. Suitable fusion partners for the Bau proteins of the invention are well known to those of skill in the art and include, among others, β-galactosidase, glutathione-S-transferase, and poly-histidine.

B. In Vivo

Alternatively, where it is desired that the Bau protein be expressed in vivo, e.g., for gene therapy purposes, an appropriate vector for delivery of Bau, or fragment thereof, may be readily selected by one of skill in the art. Exemplary gene therapy vectors are readily available from a variety of academic and commercial sources, and include, e.g., adeno-associated virus International patent application No. PCT/US91/03440!, adenovirus vectors M. Kay et al, Proc. Natl. Acad. Sci. USA, 91:2353 (1994); S. Ishibashi et al, J. Clin. Invest., 92:883 (1993)!, or other viral vectors, e.g., various poxviruses, vaccinia, etc. Methods for insertion of a desired gene, e.g. Bau, and obtaining in vivo expression of the encoded protein, are well known to those of skill in the art.

IV. Antisera and Antibodies

The Bau proteins of this invention are also useful as antigens for the development of anti-Bau antisera and antibodies to Bau or to a desired fragment of a Bau protein. Specific antisera may be generated using known techniques. See, Sambrook, cited above, Chapter 18, generally, incorporated by reference. Similarly, antibodies of the invention, both polyclonal and monoclonal, may be produced by conventional methods, including the Kohler and Milstein hybridoma technique, recombinant techniques, such as described by Huse et al, Science, 246:1275-1281 (1988), or any other techniques known to the art.

Also encompassed within this invention are humanized and chimeric antibodies. As used herein, a humanized antibody is defined as an antibody containing murine complementary determining regions (CDRs) capable of binding to Bau or a fragment thereof, and human framework regions. These CDRs are preferably derived from a murine monoclonal antibody (MAb) of the invention. As defined herein, a chimeric antibody is defined as an antibody containing the variable region light and heavy chains, including both CDR and framework regions, from a Bau MAb of the invention and the constant region light and heavy chains from a human antibody. Methods of identifying suitable human framework regions and modifying a MAb of the invention to contain same to produce a humanized or chimeric antibody of the invention, are well known to those of skill in the art. See, e.g., E. Mark and Padlin, "Humanization of Monoclonal Antibodies", Chapter 4, The Handbook of Experimental Pharmacology, Vol. 113, The Pharmacology of Monoclonal Antibodies, Springer-Verlag (June 1994). Other types of recombinantly-designed antibodies are also encompassed by this invention.

Further provided by the present invention are anti-idiotype antibodies (Ab2) and anti-anti-idiotype antibodies (Ab3). Ab2 are specific for the target to which anti-Bau antibodies of the invention bind and Ab3 are similar to Bau antibodies (Ab1) in their binding specificities and biological activities see, e.g., M. Wettendorff et al, "Modulation of anti-tumor immunity by anti-idiotypic antibodies." In Idiotypic Network and Diseases, ed. by J. Cerny and J. Hiernaux J, Am. Soc. Microbiol., Washington D.C.: pp. 203-229, (1990)!. These anti-idiotype and anti-anti-idiotype antibodies may be produced using techniques well known to those of skill in the art. Such anti-idiotype antibodies (Ab2) can bear the internal image of Bau and can thus bind to Bin1 in much the same manner as Bau, and are thus useful for the same purposes as Bau.

In general, polyclonal antisera, monoclonal antibodies and other antibodies which bind to Bau as the antigen (Ab1) are useful to identify epitopes of Bau, to separate Bau from contaminants in living tissue (e.g., in chromatographic columns and the like), and in general as research tools and as starting material essential for the development of other types of antibodies described above. Anti-idiotype antibodies (Ab2) are useful for binding BIN1 and thus may be used in the treatment of cancers in which BIN1 can affect C-MYC, which is part of a biochemical cascade of events leading to tumor formation. The Ab3 antibodies may be useful for the same reason the Ab1 are useful. Other uses as research tools and as components for separation of Bin from other contaminants of living tissue, for example, are also contemplated for these antibodies.

V. Diagnostic Reagents and Methods

Advantageously, the present invention provides reagents and methods useful in detecting and diagnosing abnormal levels of Bau, and particularly deficiencies, mutant species, or excess production of either, in a patient. As defined herein, a deficiency of Bau is an inadequate amount of Bau to compensate for the levels of BIN1 and c-MYC in a patient. Conditions associated with deficiencies of Bau may include a variety of cancers, e.g., breast cancer, liver cancer and colon cancer, and hyperplastic disease states, e.g., benign prostate hyperplasia, involving MYC activation.

Thus, the proteins, protein fragments, antibodies, and polynucleotide sequences (including anti-sense polynucleotide sequences and oligonucleotide fragments), and Bau antisera and antibodies of this invention may be useful as diagnostic reagents. These reagents may optionally be labelled using diagnostic labels, such as radioactive labels, colorimetric enzyme label systems and the like conventionally used in diagnostic or therapeutic methods. Alternatively, the N- or C-terminus of Bau or a fragment thereof may be tagged with a viral epitope which can be recognized by a specific antisera. The reagents may be used to measure abnormal Bau levels in selected mammalian tissue in conventional diagnostic assays, e.g., Southern blotting, Northern and Western blotting, polymerase chain reaction (PCR), reverse transcriptase (RT) PCR, immunostaining, and the like. For example, in biopsies of tumor tissue, loss of Bau expression in tumor tissue could be directly verified by RT-PCR or immunostaining. Alternatively, a Southern analysis, genomic PCR, or fluorescence in situ hybridization (FISH) may be performed to confirm Bau1 gene rearrangement.

In one example, as diagnostic agents the polynucleotide sequences may be employed to detect or quantitate normal Bau. The selection of the appropriate assay format and label system is within the skill of the art and may readily be chosen without requiring additional explanation by resort to the wealth of art in the diagnostic area.

Thus the present invention provides methods for the detection of disorders characterized by insufficient Bau levels. The methods involve contacting a selected mammalian tissue, e.g., a biopsy sample or other cells, with the selected reagent, protein, antisera antibody or DNA sequence, and measuring or detecting the amount of Bau present in the tissue in a selected assay format based on the binding or hybridization of the reagent to the tissue.

VI. Therapeutic Compositions and Methods

Compositions and methods useful for the treatment of conditions associated with inadequate Bau levels are provided. As stated above, included among such conditions are cancers involving MYC activation. Also provided are compositions and methods for inhibiting Bau activity in order to ameliorate a condition in which apoptosis is activated and BIN1 plays a role. Such conditions may include degenerative conditions, e.g., neurodegenerative diseases.

For example, where it is desirable to augment Bau activity in order to increase Bin1-mediated tumor suppressor activity or decrease the malignant activity of deregulated Myc, a therapeutic composition of the invention may be prepared which contains a Bau polypeptide, or a peptidomimetic drug derived from a Bau using the techniques described herein. Other Bau agonists, e.g., those identified using the methods described in Section VII below, are suitable components for a therapeutic composition which inhibits Bau activity. Such antagonists may be used in conjunction with Bau polypeptides or as alternatives thereto.

In other circumstances, such as degenerative diseases, it may be desirable to prepare therapeutic compositions which contain a Bau antagonist, such as a Bau antibody. One particularly desirable antibody would be directed against the Bin1-binding domain of Bau, located within aa 62 to 209 of SEQ ID NO:2. Other Bau antagonists, e.g., those identified using the methods described in Section VII below, may also be useful. Such antagonists may be used in conjunction with anti-Bau antibodies, or as alternatives thereto.

The therapeutic composition of the invention desirably contains 0.01 μg to 10 mg protein. These compositions may contain a pharmaceutically acceptable carrier. Suitable carriers are well known to those of skill in the art and include, for example, saline. Alternatively, such compositions may include conventional delivery systems into which protein of the invention is incorporated. Optionally, these compositions may contain other active ingredients, e.g., chemotherapeutics.

Still another method involves the use of the Bau polynucleotide sequences for gene therapy. In the method, the Bau sequences are introduced into a suitable vector for delivery to a cell containing a deficiency of Bau and/or BIN1 levels. By conventional genetic engineering techniques, the Bau gene sequence may be introduced to mutate the existing gene by recombination or to replace an inactive or missing gene.

Generally, a suitable polynucleotide-based treatment contains between 1×10⁻³ pfu to 1×10¹² pfu per dose. However, the dose, timing and mode of administration of these compositions may be determined by one of skill in the art. Such factors as the age, condition, and the level of the Bau deficiency detected by the diagnostic methods described above, may be taken into account in determining the dose, timing and mode of administration of the therapeutic compositions of the invention. Generally, where treatment of an existing cancer or hyperplastic state is indicated, a therapeutic composition of the invention is preferably administered in a site-directed manner and is repeated as needed. Such therapy may be administered in conjunction with conventional therapies, including radiation and/or chemotherapeutic treatments.

VII. Drug Screening and Development

The proteins, antibodies and polynucleotide sequences of the present invention may also be used in the screening and development of chemical compounds or proteins which have utility as therapeutic drugs for the treatment of cancers characterized by Bau or BIN1, which regulate inappropriate MYC levels. As one example, a compound capable of binding to Bau and preventing its biological activity may be a useful drug component for the treatment or prevention of cancer. The methods described herein may also be applied to fragments of Bau. One particularly suitable fragment is the Bin1-binding domain (aa 62 to 209 of SEQ ID NO:2).

Suitable assay methods may be readily determined by one of skill in the art. Where desired, and depending on the assay selected, Bau may be immobilized directly or indirectly (e.g., via an anti-Bau antibody) on a suitable surface, e.g., in an ELISA format. Such immobilization surfaces are well known. For example, a wettable inert bead may be used. Alternatively, Bau may be used in screening assays which do not require immobilization, e.g., in the screening of combinatorial libraries.

Assays and techniques exist for the screening and development of drugs capable of binding to selected regions of Bau. These include the use of phage display system for expressing the Bau proteins, and using a culture of transfected E. coli or other microorganism to produce the proteins for binding studies of potential binding compounds. See, for example, the techniques described in G. Cesarini, FEBS Letters, 307(1):66-70 (July 1992); H. Gram et al., J. Immunol. Meth., 161:169-176 (1993); C. Summer et al., Proc. Natl. Acad. Sci., USA, 89:3756-3760 (May 1992), incorporated by reference herein.

Other conventional drug screening techniques may be employed using the proteins, antibodies or polynucleotide sequences of this invention. As one example, a method for identifying compounds which specifically bind to a Bau protein can include simply the steps of contacting a selected Bau protein with a test compound to permit binding of the test compound to Bau; and determining the amount of test compound, if any, which is bound to the Bau protein. Such a method may involve the incubation of the test compound and the Bau protein immobilized on a solid support.

Typically, the surface containing the immobilized ligand is permitted to come into contact with a solution containing the Bau protein and binding is measured using an appropriate detection system. Suitable detection systems include the streptavidin horse radish peroxidase conjugate, direct conjugation by a tag, e.g., fluorescein. Other systems are well known to those of skill in the art. This invention is not limited by the detection system used.

Another method of identifying compounds which specifically bind to Bau can include the steps of contacting a Bau protein immobilized on a solid support with both a test compound and the protein sequence which is a receptor for Bau to permit binding of the receptor to the Bau protein; and determining the amount of the receptor which is bound to the Bau protein. The inhibition of binding of the normal protein by the test compound thereby indicates binding of the test compound to the Bau protein.

Thus, through use of such methods, the present invention is anticipated to provide compounds capable of interacting with Bau or portions thereof, and either enhancing or decreasing its biological activity, as desired. Such compounds are believed to be encompassed by this invention.

The assay methods described herein are also useful in screening for inhibition of the interaction between a Bau protein of the invention and BIN1 and/or another ligand(s). The solution containing the inhibitors may be obtained from any appropriate source, including, for example, extracts of supernatants from culture of bioorganisms, extracts from organisms collected from natural sources, chemical compounds, and mixtures thereof.

The following examples illustrate the isolation and use of the Bau nucleic acid sequences, polypeptides, and fragments of the invention. These examples are illustrative only and do not limit the scope of the invention.

EXAMPLE 1

Identification and Characterization of Bau

A yeast two hybrid screen was performed to identify U1-specific BIN1-binding proteins.

The two hybrid system and methodology used for the screen was similar to that used to identify the MYC-interacting protein BIN1 D. Sakamuro, et al, cited above!. A region of BIN1 (aa 214-269 of SEQ ID NO:6) that included exon 9 (U1) and 10 sequences was used as the "bait" polypeptide. U1-binding clones were screened from a murine 10.5d embryo cDNA library Vojtek et al, Cell, 74: 205-214 (1993)! on the basis of their ability to confer HIS+ and LacZ+ phenotypes to the yeast assay strain L40, after transformation with "bait" and cDNA library plasmids. A mating strategy Vojtek et al, Cell, 74:205-214 (1993)! was used to identify the U1-specific clones, using the control "baits" lamin, rhoB Sakamuro et al, cited above!, and a deletion mutant of the U1 region (containing only aa 214-229). cDNA library plasmids from U1-specific clones were shuttled into E. coli and subjected to DNA sequencing.

By this approach, two different sequences encoding U1-binding polypeptides were identified. One of the sequence classes encoded an N-terminal region of nucleophosmin, a growth-regulated protein which shuttles between the nucleolus and the nucleoplasm and is believed to play a role in the regulation of ribosome biosynthesis Yung and Chou, Biochem. Biophys. Res. Comm., 217:313-325 (1995)!. Interestingly, oncogenic translocations of nucleophosmin occur in certain non-Hodgkin's lymphomas, and Myc is known to regulate ribosomal RNA synthesis.

The second sequence was unrelated to other sequences in the DNA database (data not shown). A .sup.˜ 1 kb near-full length cDNA was obtained from a murine embryonic phage library by standard hybridization methodology and its entire DNA sequence was determined (SEQ ID NO: 1). The DNA sequence of this clone, termed Bau (for Bin1-Associated U1-specific protein), encoded a 293 amino acid hydrophilic polypeptide of predicted molecular weight 34,137 Daltons (SEQ ID NO: 2). Structure prediction analysis of Bau using the COILS algorithm A. Lupas, Meth Enz, 266: 513-525 (1996)! indicated that its N-terminal region (aa 1-160) is strongly predicted to form a coiled-coil domain (data not shown).

EXAMPLE 2

Bau Contains Motifs Found in Cysteine Protease Inhibitors and a Mitotic Checkpoint Regulator

Comparison of Bau sequences to the DNA database revealed no significant relationship to known gene products. However, analysis of Bau sequence using the BLOCKS algorithm Henikoff and Henikoff, Genomics, 19: 97-107 (1994)!, which identifies signature motifs, turned up a region shared with type I cystatins, a class of cysteine protease inhibitors. (Signature motifs are sequence homology motifs that are found in all members of a polypeptide family with similar functional characteristics.) Type I cystatins are .sup.˜ 100 aa molecules that form non-disulfide linked dimers. The signature motif in Bau is located at aa 89-105 and was 65% (11/17) identical and 76% (13/17) similar to cystatin B A. Machleidt et al., Biochem Biophys Res Commun, 131: 1187-1192 (1985)!, a liver thiol protease inhibitor of the cystatin type I family most closely related to Bau.

The cystatin similarity suggests that Bau may be able to inhibit certain cysteine protease inhibitors. This is significant because (i.) a class of ubiquitous cysteine protease inhibitors termed caspases have a effector central role in activating apoptosis, and (ii.) Bin1 has been implicated in mediating apoptosis by Myc. Based on this relationship, Bau is hypothesized to function in a Bin1-Bau-caspase signaling pathway for apoptosis.

By visual inspection, an additional relationship was identified between the Bau-cystatin motif and the yeast checkpoint regulator Mad1p Hardwick and Murray, J Cell Biol, 131: 709-720 (1995)!. Mad1p arrests mitosis in response to spindle assembly damage. Mad1p was one of a set of mitotic regulators that was examined for a suspected relationship to Bau, because of existing links between Bin1 and mitosis, namely, a localization of Bin1 at the microtubule organizing center (MTOC; spindle pole) during mitosis and an MTOC-like structure in cells destined to undergo apoptosis (G.P., unpublished observations). While it is not known yet if Bau has a mitotic role, or if Mad1p can inhibit cysteine protease activity, the Bau-cystatin motif identified in Mad1p is located at aa 83-103 and exhibits 57% (12/21) identity and 71% (15/21) similarity to the others. Bau and Mad1p also share similarity consisting of a polyasparagine region, at aa 165-169 and aa 330-372, respectively, downstream of the Bau-cystatin motif. Consistent with a functional link to apoptosis, spindle pole damage following loss of Mad1p results in an apoptosis-like death in yeast. Taken together, the structural relationship between Bau, type I cystatins, and Mad1p are consistent with a role for Bau in the regulation of Bin1-mediated apoptosis.

EXAMPLE 3

Bin1 Exons 9 (U1) and 10 are Necessary for Bau Interaction

The original two hybrid cDNAs encoded an open reading frame of at approximately 145 amino acids. This region, which constitutes a Bin1-binding domain (BBD) sufficient for Bin1 interaction, is located at aa 62-209 of Bau SEQ ID NO:2!.

To confirm the interaction between Bau and Bin1, and to define the exact regions of Bin1 required for interaction with Bau, the following in vitro biochemical analysis was performed. Various regions of Bin1, including U1, the adjacent NLS-like motif (exon 10 sequences), or U1-NLS, were expressed in E. coli by fusing them to glutathione-S-transferase (GST), using standard methodology. Unfused GST or GST fusions were purified by glutathione affinity purification, using standard methods, and employed for Bau binding experiments. Bau was engineered with a epitope tag and translation termination site at its 3' end; the Bau BBD was engineered for expression with a Kozak translation initiation site (the two hybrid cDNA subcloned included a termination site at its 3' end). For binding assays, equivalent amounts of GST proteins were mixed with ³⁵ S-methionine labeled Bau or BBD, expressed by in vitro translation in rabbit reticulocyte extracts.

Both Bau and the BBD were each observed to bind specifically to GST-U1-NLS but more poorly or not at all to GST-U1 or GST-NLS. The interaction of Bau was slightly weaker than BBD, which stable at near physiological salt concentrations (150 mM NaCl) and in 0.1% NP40 ™(octylphenoxy)polyethoxyethanol detergent (also known under the trademark IGEPAL CA-630 Sigma!. In addition, under low salt conditions (50 mM NaCl), BBD could also bind weakly to GST-NLS, a region insufficient for Bau binding under any conditions. These data were confirmed for BBD in the two hybrid system.

The results indicated that Bau association depended upon both U1 and the NLS-like motif encoded by exon 10, which was spliced into Bin1 message following induction of either cell differentiation (in the absence of Myc) or apoptosis (in the presence of deregulated Myc). These findings supported the hypothesis that Bau may participate in mediating or regulating Bin1 function during such cell fate changes.

EXAMPLE 4

Bau is Encoded by a Single Copy, Evolutionarily Conserved Gene that is Widely Expressed

To obtain evidence that Bau was a novel gene product, Southern and Northern analyses of genomic DNA and cytoplasmic RNA from murine and human cells were performed, using standard methods. Southern blots hybridized with the murine Bau cDNA revealed the presence of a single-copy bands in both murine and human DNA. The presence of evolutionarily conserved sequences strongly argued for gene identification. On Northern blots of RNA isolated from embryonic and adult murine tissues and from various human cell lines, a ubiquitously expressed RNA of approximately 1.4 kb was detected. In certain human tumor cells, such as HepG2 hepatocarcinoma cells, Bau message was not detected. Since normal murine liver expressed Bau, the lack of message in HepG2 cells suggested that Bau expression may be lost during the genesis of certain types of cancer such as hepatocarcinoma. Taken together, the data supported the assertion that Bau is encoded by a novel gene which has a tumor suppressor role like Bin1.

EXAMPLE 5

Bau Inhibits Malignant Cell Transformation

Bin1 can inhibit malignant cell transformation by Myc but also by the adenovirus E1A oncoprotein, through a Myc-independent mechanism D. Sakamuro, et al., Nature Genet, 14: 69-77 (1996)!. Inhibition of Myc is partially dependent and E1A completely dependent upon the integrity of the U1 region in Bin1 Elliott, Sakamuro et al., manuscript submitted!. Since Bau can interact with U1, we speculated that Bau might also inhibit cell transformation by Myc or E1A. To test this, Bau was assayed for the ability to suppress transformed focus formation in rat embryo fibroblasts (REFs) induced by these oncoproteins. Bau was subcloned into a mammalian expression vector so it could be tested in this assay. In addition, to assay any effect of the BBD, it was similarly subcloned for testing. As a negative control for any effects on transformation, we tested the effects of Bau or BBD on SV40 T antigen, which but is unaffected by Bin1 in this assay D. Sakamuro, et al., cited above!.

Bau and BBD was observed to inhibit the activity of E1A in this assay approximately 3-fold and 4-fold, respectively (see FIG. 4). While BBD suppressed the activity of Myc approximately 2-fold, Bau had a lesser effect that was not statistically significant (data not shown). This effect may reflect the lesser dependence of Myc for U1 in this assay. The inhibition of E1A was specific insofar as neither Bau nor BBD significantly affected transformation by T antigen. Consistent with a lack of inhibition in T antigen-transformed cells, exogenous message was detected in RNA isolated from pools of transformed colonies by Northern analysis. Taken together, the results supported the conclusion that Bau was a growth inhibitor that could interfere with certain types of malignant cell proliferation.

EXAMPLE 6

Isolation of Human Bau cDNA

Using the murine cDNA as a probe, the human Bau cDNA can be obtained from a human HeLa cell λZAPII cDNA library (Stratagene, La Jolla, Calif.) by standard methods Sambrook et al, cited above!, i.e., by hybridization with ³² P!-labeled Bau and washing under low stringency conditions (2×SSC 42° C.). The complete sequence of the human cDNA can be determined using the dideoxy method with Sequenase (US Biochemicals) and assembled and analyzed with MacVector software (IBI/Kodak).

EXAMPLE 7

Anti-Bau Antibodies

For use in generating antibodies, the Bau sequences encoding the Bin1-binding domain (BBD, aa 62 to 209 of SEQ ID NO:2) was expressed as a glutathione-S-transferase (GST) fusion protein.

To construct the GST fusion protein, the partial Bau cDNA initially isolated in the two hybrid screen was used (this cDNA encoded only the BBD as defined above). A Bam HI-Eco RI fragment including the partial cDNA was isolated from the two hybrid vector and shuttled into the baculovirus recombination vector pAcGHLT-C (Invitrogen, Inc., San Diego, Calif.). The recombinant plasmid was introduced into Sf9 insect cells. The GST-Bau₆₂₋₂₀₉ polypeptide whose synthesis was directed by the recombinant plasmid was purified from Sf9 cell extracts on glutathione-Sepharose (Pharmacia), using protocols supplied by the vendor.

To generate BBD-specific antibodies, GST-Bau₆₂₋₂₀₉ was used to immunize mice. Cells prepared from the spleens of immunized mice were processed for hybridoma production and monoclonal antibody purification, using standard protocols.

All documents cited above are incorporated herein by reference. Numerous modifications and variations of the present invention are included in the above-identified specification and are expected to be obvious to one of skill in the art. Such modifications and alterations to the compositions and processes of the present invention are believed to be encompassed in the scope of the claims appended hereto.

    __________________________________________________________________________     #             SEQUENCE LISTING     - (1) GENERAL INFORMATION:     -    (iii) NUMBER OF SEQUENCES: 8     - (2) INFORMATION FOR SEQ ID NO:1:     -      (i) SEQUENCE CHARACTERISTICS:     #pairs    (A) LENGTH: 926 base               (B) TYPE: nucleic acid               (C) STRANDEDNESS: double               (D) TOPOLOGY: unknown     -     (ii) MOLECULE TYPE: cDNA     -     (ix) FEATURE:               (A) NAME/KEY: CDS               (B) LOCATION: 48..926     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:     #TTT TCC       56ATTGAG GTCTTTGAGC TGCCTGAGAA CGAGGAC ATG     #Phe Ser         Met     #1     - CCA TCT GAC CTG GAC ACA AGC AAG CTC AGC CA - #C AAG TTC AAA GAG TTG      104     Pro Ser Asp Leu Asp Thr Ser Lys Leu Ser Hi - #s Lys Phe Lys Glu Leu     #      15     - CAA ATC AAA CAT GCA GTT ACA GAA GCA GAG AT - #T CAA AAA TTG AAG ACC      152     Gln Ile Lys His Ala Val Thr Glu Ala Glu Il - #e Gln Lys Leu Lys Thr     # 35     - AAG CTT CAA GCA TCC GAA AAT GAG AAA GTA AG - #G TGG GAA CTA GAA AAG      200     Lys Leu Gln Ala Ser Glu Asn Glu Lys Val Ar - #g Trp Glu Leu Glu Lys     #                 50     - AAC CAA CTG CAA CAG AAT ATA GAA GAG AAT AA - #A GAA CGG ATG CTG AAG      248     Asn Gln Leu Gln Gln Asn Ile Glu Glu Asn Ly - #s Glu Arg Met Leu Lys     #             65     - TTG GAG AGC TAC TGG ATC GAG GCT CAG ACA TT - #A TGT CAT ACG GTG AAT      296     Leu Glu Ser Tyr Trp Ile Glu Ala Gln Thr Le - #u Cys His Thr Val Asn     #         80     - GAG CAT CTC AAA GAG ACT CAG AGC CAG TAC CA - #A GCC CTG GAA AAG AAA      344     Glu His Leu Lys Glu Thr Gln Ser Gln Tyr Gl - #n Ala Leu Glu Lys Lys     #     95     - TAC AAC AAA GCA AAG AAG CTG ATC AAA GAC TT - #C CAG CAA AAA GAG CTC      392     Tyr Asn Lys Ala Lys Lys Leu Ile Lys Asp Ph - #e Gln Gln Lys Glu Leu     100                 1 - #05                 1 - #10                 1 -     #15     - GAT TTC ATC AAG AGA CAG GAA GTA GAA AGA AA - #G AAG CGG GAG GAG GTG      440     Asp Phe Ile Lys Arg Gln Glu Val Glu Arg Ly - #s Lys Arg Glu Glu Val     #               130     - GAA AAG GCT CAC CTG CTT GAA GTC CAA GGC CT - #G CAA GTT CGG ATT AGA      488     Glu Lys Ala His Leu Leu Glu Val Gln Gly Le - #u Gln Val Arg Ile Arg     #           145     - GAT TTG GAG GCT GAG GTG TTC AGA CTA CTA AA - #G CAA AAT GGG ACC CAG      536     Asp Leu Glu Ala Glu Val Phe Arg Leu Leu Ly - #s Gln Asn Gly Thr Gln     #       160     - GTT AAC AAC AAC AAC AAC ATC TTT GAG AGA AG - #A CCA TCT CCC GGG GAA      584     Val Asn Asn Asn Asn Asn Ile Phe Glu Arg Ar - #g Pro Ser Pro Gly Glu     #   175     - GTC TCG AAA GGA GAC ACT ATG GAG AAT GTG GA - #A GTC AAG CAA ACA TCC      632     Val Ser Lys Gly Asp Thr Met Glu Asn Val Gl - #u Val Lys Gln Thr Ser     180                 1 - #85                 1 - #90                 1 -     #95     - TGT CAG GAC GGC TTG AGC CAA GAC CTG AAT GA - #A GCA GTC CCA GAG ACA      680     Cys Gln Asp Gly Leu Ser Gln Asp Leu Asn Gl - #u Ala Val Pro Glu Thr     #               210     - GAG CGC CTG GAT TCG AAA GCA TTG AAA ACC CG - #G GCC CAG CTC TCT GTG      728     Glu Arg Leu Asp Ser Lys Ala Leu Lys Thr Ar - #g Ala Gln Leu Ser Val     #           225     - AAG AAC AGG CGC CAG AGG CCC ACA AGG ACA CG - #G CTC TAT GAC AGC GTC      776     Lys Asn Arg Arg Gln Arg Pro Thr Arg Thr Ar - #g Leu Tyr Asp Ser Val     #       240     - AGC TCA ACT GAT GGG GAG GAC AGC CTG GAG AG - #G AAG GTG AGC ACT CTC      824     Ser Ser Thr Asp Gly Glu Asp Ser Leu Glu Ar - #g Lys Val Ser Thr Leu     #   255     - AAT GGC TGG CAG ACT CTT GCA GAG TGT CGT TG - #T CCA CCA GTG TAT TTA      872     Asn Gly Trp Gln Thr Leu Ala Glu Cys Arg Cy - #s Pro Pro Val Tyr Leu     260                 2 - #65                 2 - #70                 2 -     #75     - TTG AAC GTG ATA GCG GTT TTA CTG ATC TGT GC - #C TTA CTT GGA AGA AAG      920     Leu Asn Val Ile Ala Val Leu Leu Ile Cys Al - #a Leu Leu Gly Arg Lys     #               290     #          926     Ser Pro     - (2) INFORMATION FOR SEQ ID NO:2:     -      (i) SEQUENCE CHARACTERISTICS:     #acids    (A) LENGTH: 293 amino               (B) TYPE: amino acid               (D) TOPOLOGY: linear     -     (ii) MOLECULE TYPE: protein     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:     - Met Phe Ser Pro Ser Asp Leu Asp Thr Ser Ly - #s Leu Ser His Lys Phe     #                 15     - Lys Glu Leu Gln Ile Lys His Ala Val Thr Gl - #u Ala Glu Ile Gln Lys     #             30     - Leu Lys Thr Lys Leu Gln Ala Ser Glu Asn Gl - #u Lys Val Arg Trp Glu     #         45     - Leu Glu Lys Asn Gln Leu Gln Gln Asn Ile Gl - #u Glu Asn Lys Glu Arg     #     60     - Met Leu Lys Leu Glu Ser Tyr Trp Ile Glu Al - #a Gln Thr Leu Cys His     # 80     - Thr Val Asn Glu His Leu Lys Glu Thr Gln Se - #r Gln Tyr Gln Ala Leu     #                 95     - Glu Lys Lys Tyr Asn Lys Ala Lys Lys Leu Il - #e Lys Asp Phe Gln Gln     #           110     - Lys Glu Leu Asp Phe Ile Lys Arg Gln Glu Va - #l Glu Arg Lys Lys Arg     #       125     - Glu Glu Val Glu Lys Ala His Leu Leu Glu Va - #l Gln Gly Leu Gln Val     #   140     - Arg Ile Arg Asp Leu Glu Ala Glu Val Phe Ar - #g Leu Leu Lys Gln Asn     145                 1 - #50                 1 - #55                 1 -     #60     - Gly Thr Gln Val Asn Asn Asn Asn Asn Ile Ph - #e Glu Arg Arg Pro Ser     #               175     - Pro Gly Glu Val Ser Lys Gly Asp Thr Met Gl - #u Asn Val Glu Val Lys     #           190     - Gln Thr Ser Cys Gln Asp Gly Leu Ser Gln As - #p Leu Asn Glu Ala Val     #       205     - Pro Glu Thr Glu Arg Leu Asp Ser Lys Ala Le - #u Lys Thr Arg Ala Gln     #   220     - Leu Ser Val Lys Asn Arg Arg Gln Arg Pro Th - #r Arg Thr Arg Leu Tyr     225                 2 - #30                 2 - #35                 2 -     #40     - Asp Ser Val Ser Ser Thr Asp Gly Glu Asp Se - #r Leu Glu Arg Lys Val     #               255     - Ser Thr Leu Asn Gly Trp Gln Thr Leu Ala Gl - #u Cys Arg Cys Pro Pro     #           270     - Val Tyr Leu Leu Asn Val Ile Ala Val Leu Le - #u Ile Cys Ala Leu Leu     #       285     - Gly Arg Lys Ser Pro         290     - (2) INFORMATION FOR SEQ ID NO:3:     -      (i) SEQUENCE CHARACTERISTICS:     #pairs    (A) LENGTH: 402 base               (B) TYPE: nucleic acid               (C) STRANDEDNESS: double               (D) TOPOLOGY: unknown     -     (ii) MOLECULE TYPE: cDNA     -     (ix) FEATURE:               (A) NAME/KEY: CDS               (B) LOCATION: 1..399     -     (ix) FEATURE:               (A) NAME/KEY: mat.sub.-- - #peptide               (B) LOCATION: 1     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:     - GAG ATC AGA GTG AAC CAT GAG CCA GAG CCG GC - #C AGT GGG GCC TCA CCC       48     Glu Ile Arg Val Asn His Glu Pro Glu Pro Al - #a Ser Gly Ala Ser Pro     #                 15     - GGG GCT GCC ATC CCC AAG TCC CCA TCT CAG CC - #A GCA GAG GCC TCC GAG       96     Gly Ala Ala Ile Pro Lys Ser Pro Ser Gln Pr - #o Ala Glu Ala Ser Glu     #             30     - GTG GTG GGT GGA GCC CAG GAG CCA GGG GAG AC - #A GCA GCC AGT GAA GCA      144     Val Val Gly Gly Ala Gln Glu Pro Gly Glu Th - #r Ala Ala Ser Glu Ala     #         45     - ACC TCC AGC TCT CTT CCG GCT GTG GTG GTG GA - #G ACC TTC TCC GCA ACT      192     Thr Ser Ser Ser Leu Pro Ala Val Val Val Gl - #u Thr Phe Ser Ala Thr     #     60     - GTG AAT GGG GCG GTG GAG GGC AGC GCT GGG AC - #T GGA CGC TTG GAC CTG      240     Val Asn Gly Ala Val Glu Gly Ser Ala Gly Th - #r Gly Arg Leu Asp Leu     # 80     - CCC CCG GGA TTC ATG TTC AAG GTT CAA GCC CA - #G CAT GAT TAC ACG GCC      288     Pro Pro Gly Phe Met Phe Lys Val Gln Ala Gl - #n His Asp Tyr Thr Ala     #                 95     - ACT GAC ACT GAT GAG CTG CAA CTC AAA GCT GG - #C GAT GTG GTG TTG GTG      336     Thr Asp Thr Asp Glu Leu Gln Leu Lys Ala Gl - #y Asp Val Val Leu Val     #           110     - ATT CCT TTC CAG AAC CCA GAG GAG CAG GAT GA - #A GGC TGG CTC ATG GGT      384     Ile Pro Phe Gln Asn Pro Glu Glu Gln Asp Gl - #u Gly Trp Leu Met Gly     #       125     # 402              AC TGA     Val Lys Glu Ser Asp         130     - (2) INFORMATION FOR SEQ ID NO:4:     -      (i) SEQUENCE CHARACTERISTICS:     #acids    (A) LENGTH: 133 amino               (B) TYPE: amino acid               (D) TOPOLOGY: linear     -     (ii) MOLECULE TYPE: protein     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:     - Glu Ile Arg Val Asn His Glu Pro Glu Pro Al - #a Ser Gly Ala Ser Pro     #                 15     - Gly Ala Ala Ile Pro Lys Ser Pro Ser Gln Pr - #o Ala Glu Ala Ser Glu     #             30     - Val Val Gly Gly Ala Gln Glu Pro Gly Glu Th - #r Ala Ala Ser Glu Ala     #         45     - Thr Ser Ser Ser Leu Pro Ala Val Val Val Gl - #u Thr Phe Ser Ala Thr     #     60     - Val Asn Gly Ala Val Glu Gly Ser Ala Gly Th - #r Gly Arg Leu Asp Leu     # 80     - Pro Pro Gly Phe Met Phe Lys Val Gln Ala Gl - #n His Asp Tyr Thr Ala     #                 95     - Thr Asp Thr Asp Glu Leu Gln Leu Lys Ala Gl - #y Asp Val Val Leu Val     #           110     - Ile Pro Phe Gln Asn Pro Glu Glu Gln Asp Gl - #u Gly Trp Leu Met Gly     #       125     - Val Lys Glu Ser Asp         130     - (2) INFORMATION FOR SEQ ID NO:5:     -      (i) SEQUENCE CHARACTERISTICS:     #pairs    (A) LENGTH: 1925 base               (B) TYPE: nucleic acid               (C) STRANDEDNESS: double               (D) TOPOLOGY: unknown     -     (ii) MOLECULE TYPE: cDNA     -     (ix) FEATURE:               (A) NAME/KEY: CDS               (B) LOCATION: 60..1412     -     (ix) FEATURE:               (A) NAME/KEY: mat.sub.-- - #peptide               (B) LOCATION: 60     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:     - GAATTCCGTG CTGGTTGAGC TTGCTCATCT CCTTGTGGAA GTTTTCCTCC AG - #GCCCGCG       59     - ATG CTC TGG AAC GTG GTG ACG GCG GGA AAG AT - #C GCC AGC AAC GTG CAG      107     Met Leu Trp Asn Val Val Thr Ala Gly Lys Il - #e Ala Ser Asn Val Gln     #                 15     - AAG AAG CTC ACC CGC GCG CAG GAG AAG GTT CT - #C CAG AAG CTG GGG AAG      155     Lys Lys Leu Thr Arg Ala Gln Glu Lys Val Le - #u Gln Lys Leu Gly Lys     #             30     - GCA GAT GAG ACC AAG GAT GAG CAG TTT GAG CA - #G TGC GTC CAG AAT TTC      203     Ala Asp Glu Thr Lys Asp Glu Gln Phe Glu Gl - #n Cys Val Gln Asn Phe     #         45     - AAC AAG CAG CTG ACG GAG GGC ACC CGG CTG CA - #G AAG GAT CTC CGG ACC      251     Asn Lys Gln Leu Thr Glu Gly Thr Arg Leu Gl - #n Lys Asp Leu Arg Thr     #     60     - TAC CTG GCC TCC GTC AAA GCC ATG CAC GAG GC - #T TCC AAG AAG CTG AAT      299     Tyr Leu Ala Ser Val Lys Ala Met His Glu Al - #a Ser Lys Lys Leu Asn     # 80     - GAG TGT CTG CAG GAG GTG TAT GAG CCC GAT TG - #G CCC GGC AGG GAT GAG      347     Glu Cys Leu Gln Glu Val Tyr Glu Pro Asp Tr - #p Pro Gly Arg Asp Glu     #                 95     - GCA AAC AAG ATC GCA GAG AAC AAC GAC CTG CT - #G TGG ATG GAT TAC CAC      395     Ala Asn Lys Ile Ala Glu Asn Asn Asp Leu Le - #u Trp Met Asp Tyr His     #           110     - CAG AAG CTG GTG GAC CAG GCG CTG CTG ACC AT - #G GAC ACG TAC CTG GGC      443     Gln Lys Leu Val Asp Gln Ala Leu Leu Thr Me - #t Asp Thr Tyr Leu Gly     #       125     - CAG TTC CCC GAC ATC AAG TCA CGC ATT GCC AA - #G CGG GGG CGC AAG CTG      491     Gln Phe Pro Asp Ile Lys Ser Arg Ile Ala Ly - #s Arg Gly Arg Lys Leu     #   140     - GTG GAC TAC GAC AGT GCC CGG CAC CAC TAC GA - #G TCC CTT CAA ACT GCC      539     Val Asp Tyr Asp Ser Ala Arg His His Tyr Gl - #u Ser Leu Gln Thr Ala     145                 1 - #50                 1 - #55                 1 -     #60     - AAA AAG AAG GAT GAA GCC AAA ATT GCC AAG GC - #C GAG GAG GAG CTC ATC      587     Lys Lys Lys Asp Glu Ala Lys Ile Ala Lys Al - #a Glu Glu Glu Leu Ile     #               175     - AAA GCC CAG AAG GTG TTT GAG GAG ATG AAT GT - #G GAT CTG CAG GAG GAG      635     Lys Ala Gln Lys Val Phe Glu Glu Met Asn Va - #l Asp Leu Gln Glu Glu     #           190     - CTG CCG TCC CTG TGG AAC AGC CGC GTA GGT TT - #C TAC GTC AAC ACG TTC      683     Leu Pro Ser Leu Trp Asn Ser Arg Val Gly Ph - #e Tyr Val Asn Thr Phe     #       205     - CAG AGC ATC GCG GGC CTG GAG GAA AAC TTC CA - #C AAG GAG ATG AGC AAG      731     Gln Ser Ile Ala Gly Leu Glu Glu Asn Phe Hi - #s Lys Glu Met Ser Lys     #   220     - CTC AAC CAG AAC CTC AAT GAT GTG CTG GTC GG - #C CTG GAG AAG CAA CAC      779     Leu Asn Gln Asn Leu Asn Asp Val Leu Val Gl - #y Leu Glu Lys Gln His     225                 2 - #30                 2 - #35                 2 -     #40     - GGG AGC AAC ACC TTC ACG GTC AAG GCC CAG CC - #C AGA AAG AAA AGT AAA      827     Gly Ser Asn Thr Phe Thr Val Lys Ala Gln Pr - #o Arg Lys Lys Ser Lys     #               255     - CTG TTT TCG CGG CTG CGC AGA AAG AAG AAC AG - #T GAC AAC GCG CCT GCA      875     Leu Phe Ser Arg Leu Arg Arg Lys Lys Asn Se - #r Asp Asn Ala Pro Ala     #           270     - AAA GGG AAC AAG AGC CCT TCG CCT CCA GAT GG - #C TCC CCT GCC GCC ACC      923     Lys Gly Asn Lys Ser Pro Ser Pro Pro Asp Gl - #y Ser Pro Ala Ala Thr     #       285     - CCC GAG ATC AGA GTC AAC CAC GAG CCA GAG CC - #G GCC GGC GGG GCC ACG      971     Pro Glu Ile Arg Val Asn His Glu Pro Glu Pr - #o Ala Gly Gly Ala Thr     #   300     - CCC GGG GCC ACC CTC CCC AAG TCC CCA TCT CA - #G CCA GCA GAG GCC TCG     1019     Pro Gly Ala Thr Leu Pro Lys Ser Pro Ser Gl - #n Pro Ala Glu Ala Ser     305                 3 - #10                 3 - #15                 3 -     #20     - GAG GTG GCG GGT GGG ACC CAA CCT GCG GCT GG - #A GCC CAG GAG CCA GGG     1067     Glu Val Ala Gly Gly Thr Gln Pro Ala Ala Gl - #y Ala Gln Glu Pro Gly     #               335     - GAG ACT TCT GCA AGT GAA GCA GCC TCC AGC TC - #T CTT CCT GCT GTC GTG     1115     Glu Thr Ser Ala Ser Glu Ala Ala Ser Ser Se - #r Leu Pro Ala Val Val     #           350     - GTG GAG ACC TTC CCA GCA ACT GTG AAT GGC AC - #C GTG GAG GGC GGC AGT     1163     Val Glu Thr Phe Pro Ala Thr Val Asn Gly Th - #r Val Glu Gly Gly Ser     #       365     - GGG GCC GGG CGC TTG GAC CTG CCC CCA GGT TT - #C ATG TTC AAG GTA CAG     1211     Gly Ala Gly Arg Leu Asp Leu Pro Pro Gly Ph - #e Met Phe Lys Val Gln     #   380     - GCC CAG CAC GAC TAC ACG GCC ACT GAC ACA GA - #C GAG CTG CAG CTC AAG     1259     Ala Gln His Asp Tyr Thr Ala Thr Asp Thr As - #p Glu Leu Gln Leu Lys     385                 3 - #90                 3 - #95                 4 -     #00     - GCT GGT GAT GTG GTG CTG GTG ATC CCC TTC CA - #G AAC CCT GAA GAG CAG     1307     Ala Gly Asp Val Val Leu Val Ile Pro Phe Gl - #n Asn Pro Glu Glu Gln     #               415     - GAT GAA GGC TGG CTC ATG GGC GTG AAG GAG AG - #C GAC TGG AAC CAG CAC     1355     Asp Glu Gly Trp Leu Met Gly Val Lys Glu Se - #r Asp Trp Asn Gln His     #           430     - AAG AAG CTG GAG AAG TGC CGT GGC GTC TTC CC - #C GAG AAC TTC ACT GAG     1403     Lys Lys Leu Glu Lys Cys Arg Gly Val Phe Pr - #o Glu Asn Phe Thr Glu     #       445     - AGG GTC CCA TGACGGCGGG GCCCAGGCAG CCTCCGGGCG TGTGAAGAA - #C     1452     Arg Val Pro         450     - ACCTCCTCCC GAAAAATGTG TGGTTCTTTT TTTTGTTTTG TTTTCGTTTT TC - #ATCTTTTG     1512     - AAGAGCAAAG GGAAATCAAG AGGAGACCCC CAGGCAGAGG GGCGTTCTCC CA - #AAGTTTAG     1572     - GTCGTTTTCC AAAGAGCCGC GTCCCGGCAA GTCCGGCGGA ATTCACCAGT GT - #TCCTGAAG     1632     - CTGCTGTGTC CTCTAGTTGA GTTTCTGGCG CCCCTGCCTG TGCCCGCATG TG - #TGCCTGGC     1692     - CGCAGGGCGG GGCTGGGGGC TGCCGAGCCA CCATACTTAA CTGAAGCTTC GG - #CCGCACCA     1752     - CCCGGGGAAG GGTCCTCTTT TCCTGGCAGC TGCTGTGGGT GGGGCCCAGA CA - #CCAGCCTA     1812     - GCCTGCTCTG CCCCGCAGAC GGTCTGTGTG CTGTTTGAAA ATAAATCTTA GT - #GTTCAAAA     1872     - CAAAATGAAA CAAAAAAAAA AATGATAAAA ACTCTCAAAA AAACAAGGAA TT - #C     1925     - (2) INFORMATION FOR SEQ ID NO:6:     -      (i) SEQUENCE CHARACTERISTICS:     #acids    (A) LENGTH: 451 amino               (B) TYPE: amino acid               (D) TOPOLOGY: linear     -     (ii) MOLECULE TYPE: protein     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:     - Met Leu Trp Asn Val Val Thr Ala Gly Lys Il - #e Ala Ser Asn Val Gln     #                 15     - Lys Lys Leu Thr Arg Ala Gln Glu Lys Val Le - #u Gln Lys Leu Gly Lys     #             30     - Ala Asp Glu Thr Lys Asp Glu Gln Phe Glu Gl - #n Cys Val Gln Asn Phe     #         45     - Asn Lys Gln Leu Thr Glu Gly Thr Arg Leu Gl - #n Lys Asp Leu Arg Thr     #     60     - Tyr Leu Ala Ser Val Lys Ala Met His Glu Al - #a Ser Lys Lys Leu Asn     # 80     - Glu Cys Leu Gln Glu Val Tyr Glu Pro Asp Tr - #p Pro Gly Arg Asp Glu     #                 95     - Ala Asn Lys Ile Ala Glu Asn Asn Asp Leu Le - #u Trp Met Asp Tyr His     #           110     - Gln Lys Leu Val Asp Gln Ala Leu Leu Thr Me - #t Asp Thr Tyr Leu Gly     #       125     - Gln Phe Pro Asp Ile Lys Ser Arg Ile Ala Ly - #s Arg Gly Arg Lys Leu     #   140     - Val Asp Tyr Asp Ser Ala Arg His His Tyr Gl - #u Ser Leu Gln Thr Ala     145                 1 - #50                 1 - #55                 1 -     #60     - Lys Lys Lys Asp Glu Ala Lys Ile Ala Lys Al - #a Glu Glu Glu Leu Ile     #               175     - Lys Ala Gln Lys Val Phe Glu Glu Met Asn Va - #l Asp Leu Gln Glu Glu     #           190     - Leu Pro Ser Leu Trp Asn Ser Arg Val Gly Ph - #e Tyr Val Asn Thr Phe     #       205     - Gln Ser Ile Ala Gly Leu Glu Glu Asn Phe Hi - #s Lys Glu Met Ser Lys     #   220     - Leu Asn Gln Asn Leu Asn Asp Val Leu Val Gl - #y Leu Glu Lys Gln His     225                 2 - #30                 2 - #35                 2 -     #40     - Gly Ser Asn Thr Phe Thr Val Lys Ala Gln Pr - #o Arg Lys Lys Ser Lys     #               255     - Leu Phe Ser Arg Leu Arg Arg Lys Lys Asn Se - #r Asp Asn Ala Pro Ala     #           270     - Lys Gly Asn Lys Ser Pro Ser Pro Pro Asp Gl - #y Ser Pro Ala Ala Thr     #       285     - Pro Glu Ile Arg Val Asn His Glu Pro Glu Pr - #o Ala Gly Gly Ala Thr     #   300     - Pro Gly Ala Thr Leu Pro Lys Ser Pro Ser Gl - #n Pro Ala Glu Ala Ser     305                 3 - #10                 3 - #15                 3 -     #20     - Glu Val Ala Gly Gly Thr Gln Pro Ala Ala Gl - #y Ala Gln Glu Pro Gly     #               335     - Glu Thr Ser Ala Ser Glu Ala Ala Ser Ser Se - #r Leu Pro Ala Val Val     #           350     - Val Glu Thr Phe Pro Ala Thr Val Asn Gly Th - #r Val Glu Gly Gly Ser     #       365     - Gly Ala Gly Arg Leu Asp Leu Pro Pro Gly Ph - #e Met Phe Lys Val Gln     #   380     - Ala Gln His Asp Tyr Thr Ala Thr Asp Thr As - #p Glu Leu Gln Leu Lys     385                 3 - #90                 3 - #95                 4 -     #00     - Ala Gly Asp Val Val Leu Val Ile Pro Phe Gl - #n Asn Pro Glu Glu Gln     #               415     - Asp Glu Gly Trp Leu Met Gly Val Lys Glu Se - #r Asp Trp Asn Gln His     #           430     - Lys Lys Leu Glu Lys Cys Arg Gly Val Phe Pr - #o Glu Asn Phe Thr Glu     #       445     - Arg Val Pro         450     - (2) INFORMATION FOR SEQ ID NO:7:     -      (i) SEQUENCE CHARACTERISTICS:     #acids    (A) LENGTH: 5 amino               (B) TYPE: amino acid               (C) STRANDEDNESS:               (D) TOPOLOGY: unknown     -     (ii) MOLECULE TYPE: peptide     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:     - Leu Xaa Gly Xaa Glu     1               5     - (2) INFORMATION FOR SEQ ID NO:8:     -      (i) SEQUENCE CHARACTERISTICS:     #acids    (A) LENGTH: 5 amino               (B) TYPE: amino acid               (C) STRANDEDNESS:               (D) TOPOLOGY: unknown     -     (ii) MOLECULE TYPE: peptide     -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:     - Leu Xaa Cys Xaa Glu     1               5     __________________________________________________________________________ 

What is claimed is:
 1. A mammalian nucleic acid sequence encoding a BIN1-Associated U1-specific protein (Bau) or a fragment thereof, isolated from cellular materials with which it is naturally associated and selected from the group consisting of:(a) SEQ ID NO:1; and (b) a fragment of (a) comprising at least 15 consecutive nucleotides.
 2. The sequence according to claim 1 which encodes murine Bau SEQ ID NO:
 2. 3. The sequence according to claim 1, wherein the Bau fragment is selected from the group consisting of:(a) nt 231 to 674 of SEQ ID NO:1; (b) nt 48 to 527 of SEQ ID NO:1; (c) nt 312 to 362 of SEQ ID NO:1; (d) nt 294 to 356 of SEQ ID NO: 1; and (e) nt 540 to 554 of SEQ ID NO:1.
 4. A vector comprising a mammalian nucleic acid sequence according to claim
 1. 5. A host cell transformed with the vector according to claim
 4. 6. An oligonucleotide probe comprising a nucleic acid sequence selected from the group consisting of:(a) SEQ ID NO:1; (b) a sequence fully complementary to SEQ ID NO:1; and (c) a nucleic acid fragment of (a) or (b) comprising at least 15 consecutive nucleotides in length, and a detectable label, which is associated with said sequence.
 7. A murine cDNA sequence SEQ ID NO: 1 isolated from cellular materials with which it is naturally associated, which encodes a Bau polypeptide. 